I made them each a pair of wide leg lounge pants, and then decided they needed a robe too. I used Burda pattern 9690, and I was pretty pleased with the results.
There have been so many times, when a nice robe would come in handy. You know, those late afternoons when they have been outside, and their clothes are too wet or dirty to come in the house with them. I think a robe will be the perfect thing to slip on instead of getting dressed again.
I used terry cloth fabric, and lined it with some Alexander Henry fabric from Joann's.